The Leftovers star, 43, wore a sharp black suit with a skinny tie and his main squeeze, 45, swept her hair back, wearing a tan dress with black lace.
"Justin stared at her lovingly as she posed by herself," an eyewitness told Us Weekly of the couple's red carpet demeanor. "You could tell he is very in awe of her."
Once inside the awards show, the pair didn't turn down the PDA. Another eyewitness called them "extremely affectionate."
"Every time I saw them they were touching," the source tells Us. "She would lay her head on his shoulder while the different honorees were speaking onstage and put her arms around him. He also was holding her hand at the table, and I saw him lean over and kiss her a couple of times."
For more details on the couple's plans, pick up the new issue of Us Weekly on stands now!
Sign up now for the Us Weekly newsletter to get breaking celebrity news, hot pics and more delivered straight to your inbox!